Importance of Air Filter Replacement

Monday, November 20, 2017 7:10 PM

Air in your commercial office space is completely exchanged an average of 10 or more times every hour of every day that the system is operated. Areas with higher heat gains such as server rooms can exceed 20 or more complete air exchanges per hour. Also and unlike most residential systems, commercial HVAC systems bring in air from the outside to meet Minimum Code Ventilation requirements or up to 100% outside air during economizer operation. And lastly, most commercial systems are either in heating or cooling mode during the building’s occupancy schedule and rarely do the blowers shut off for any significant amount of time.

What this means to you is that the air filters should be changed much more frequently than residential systems. Also, the media has as much to do with frequency as the amount of air that passes through the air filters. Cheap 1” or 2” “bottle cap” filters with wound fiberglass strands don’t do a very good job of filtration, and much of the air and smaller dirt particles go right through.

The primary function for air filters is to protect the evaporator coil and any other components in the HVAC unit. The return ductwork is where much of the dirt falls out of the airstream and collects on grilles and inside duct surfaces. While it is true that they do help with indoor air quality, they are not “vacuum cleaners” that will keep your house or building free of dust. People coming and going from buildings create much of the dirt that’s dragged in every day.

Pleated filters do a much better job of filtering smaller particles, but the downsides are initial cost and increased static pressure drop due to the denser media. The filtration is better as the filter gets dirty, however it will start presenting higher resistance as it loads up with dirty. Eventually, they collapse and release loose dirt into the HVAC unit. Also as the static pressure increases, more and more air bypasses the filters by being drawn around the seams of the air filters. The only way to prevent that from happening is by using a prefabricated filter housing with gasketed tracks and doors.

Why you shouldn't ignore preventive maintenance.

Many people put off going regularly to their physician, dentist, or eye doctor because ongoing “maintenance” is not important to them. Most people don’t like visiting any of these health care professionals because it’s inconvenient, expensive, or unpleasant. Some of the same people and others never change their car’s engine oil, rotate the tires or wax the paint. And who wouldn’t want to avoid the expense and hassle of having regular maintenance performed by those who do it for a living.

Whether it’s your health or your car or whatever needs “maintenance”, it’s a proven fact that if you want to live longer or driver your car longer, regular maintenance is essential. The average useful life of a commercial HVAC unit is about 15-20 years and while a poorly maintained unit might continue to function for 20 years, it will have cost the owner much more in repair and utility bills. And it certainly won’t last as long as a well maintained counterpart.

Air filter changes, belts, bearings, cleaning of coils and tubes, cleaning of heat exchangers, ignitors, etc. will all cost money, however, the equipment will last longer and operate more efficiently, period. Like that old commercial said “Pay me now, or pay me later”

How building automation systems can help to improve your facility.

Just about every manufacturer installs or offers some form of communication device that will allow users to see exactly what’s going on with their equipment. From a simple local panel to an elaborate system of panels and main computer that connect entire systems together or just upgraded “smart thermostats” that can be accessed remotely via smart phones, the BAS is here to stay.

Energy savings, predictive maintenance and remote diagnosis make the decision to incorporate BAS technology in your facility. What you can do is almost limitless, given a budget that supports the scope. Most new systems are “open protocol” which allows owners and contractors alike to avoid getting stuck with a system that requires expensive updates. Make sure you do your homework before you select a system that can only be serviced by the manufacturer.